Avalanche Forecast
Issued: Jan 18th, 2025 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
Avalanche Canada,
Avalanche Canada
The persistent slab problem has produced very large avalanches recently.
Human triggering is likely, so don't let clear weather lure you into consequential terrain.
Summary
Confidence
Moderate
Avalanche Summary
On Friday, natural and rider-triggered avalanche activity continued up to size 2.5, with many persistent slabs failing on the early December weak layer between 50 and 150 cm deep.
Natural avalanche activity will likely taper over the weekend but the snowpack may be primed for human triggering.
Snowpack Summary
40 to 80 cm of storm snow fell across the region earlier in the week. Strong to extreme west through southwest wind created widespread wind-loading, with deeper deposits of snow found on leeward slopes. The winds are forecast to change directions which may start to load southerly aspects throughout the weekend.
At upper elevations down 30 to 60 cm a layer of surface hoar, facets, or a thin crust exists.
A persistent weak layer of surface hoar and facets overlying a crust is buried 100 to 200 cm deep. This layer was reactive during the storm, producing large and dangerous avalanches.
Weather Summary
Saturday Night
Clear. 10 to 20 km/h north ridgetop wind. Treeline temperature -15 °C.
Sunday
Mostly clear. 10 km/h northeast ridgetop wind, switching 20 km/h west ridgetop wind. Treeline temperature -15 °C.
Monday
Partly cloudy with trace snow. 30 gusting to 65 km/h southwest ridgetop wind. Treeline temperature -10.
Tuesday
Partly cloudy. 20 to 40 km/h west ridgetop wind. Treeline temperature -10 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Avoid freshly wind-loaded terrain features.
- Keep in mind that human triggering may persist as natural avalanches taper off.
- Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
Problems
Persistent Slabs
This problem has resulted in large and very large avalanches, up to size 3.5. Natural avalanche activity will start to taper but human-triggered avalanches remain likely.
Watch for areas where the snowpack is thin around rocks.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Watch for reactive deposits of wind slab, especially on northeast-facing slopes.
These slabs may step down to deeper persistent weak layers creating very large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 19th, 2025 4:00PM
